That bike is worth paying $300 for, compared to everything you can get new on BD and what I saw on SD craigslist. People have a strange aversion to "conversions" even though most new "track bikes" have very similar geometry. But that is a fine built bike, and from what I can tell it has parts that will be nice for what you plan to do with it. The only thing is if you plan to keep riding it as a fixed gear you really should get cages for the pedals. Its only another $20 or so.